The present invention relates to IC cards and IC chip modules and in particular to IC cards and IC chip modules with enhanced security.
A communication system employing a non-contact IC card is used for automatic ticket-gates of ski lifts, railroads and the like, automatic freight-sorting, and the like. FIG. 15 is a perspective view showing one example of a conventional non-contact IC card. An IC card 2 shown in FIG. 15 is a 1-coil IC card comprised of a coil 4 used as an antenna, capacitors C1 and C2, and an IC chip 8.
Capacitors C1, C2 and IC chip 8 are mounted to a synthetic resin substrate in the form of a film. The substrate with capacitors C1, C2 and IC chip 8 mounted thereto is referred to as a tape automated bonding (tab) 10.
FIG. 16A is a cross section of the FIG. 15 IC card 2 taken along line S1xe2x80x94S1. In the figure, a core member 12 of synthetic resin is sandwiched by paired surface members 14 and 16. Tab 10 with capacitors C1, C2 and IC chip 8 mounted thereto is fixed to surface member 14 exposed in a cavity 18 provided in core member 12. A joint of tab 10 and IC chip 8 is covered with a sealing agent 9 such as epoxy resin. Coil 4 is arranged between surface member 14 and core member 12. Coil 4 and tab 10 are connected together via a wire 20.
FIG. 16B is a circuit diagram of IC card 2. Referring to the figure, in IC card 2 an electromagnetic wave sent from a reader/writer (an interrogator (not shown)) is received at a resonator circuit 22 configured of coil 4 and capacitor C1 and it is used as a power supply. It should be noted that capacitor C2 is a power smoothing capacitor.
Furthermore, information superimposed on the electromagnetic wave and thus sent therewith is decrypted by a control unit (not shown) provided in IC chip 8. The control unit then rewrites a content of a non-volatile memory (not shown) provided in IC chip 8, makes a response to the reader/writer, and the like. The response is made by varying an impedance of resonator circuit 22. The reader/write obtains the content of the response by detecting an impedance variation (an impedance reflection) of its resonator circuit (not shown) that is associated with the impedance variation of IC card 2 resonator circuit 22.
As such, IC card 2 does not require an internal power supply and also allows non-contact communication of data.
However, conventional IC card 2 has the following disadvantage: in conventional IC card 2, a pad (or a terminal) (not shown) used for checking the performance of a mounted non-volatile memory or the like in the process for manufacturing the same is provided on a surface of IC chip 8. As such, the pad is exposed when surface members 14, 16 are removed. By applying a probe (an inspecting needle) on the exposed pad, the data in the non-volatile memory can readily be read and IC chip 8 can be operated. That is, the conventional IC card does not have high data security. Furthermore, as shown in FIG. 17, there is also an IC card which mounts to tab 10 two IC chips, i.e., an IC chip 6 with a control unit (not shown) and an IC chip 7 with a non-volatile memory (not shown). In such a type of IC card, in addition to the pad mentioned above a wire 24 connecting two IC chips 6 and 7 together is also exposed, which further facilitates reading the data stored in the non-volatile memory.
The present invention has been made to overcome the above disadvantages and contemplates an IC card and IC chip module with enhanced data security.
To achieve the above object, in one aspect of the present invention an IC card is comprised of an IC chip provided with an IC circuit, a housing body disposed to house the IC chip, and an exposure detection unit disposed to detect opened condition of the housing body, characterized in that when the exposure detection unit detects that the housing body has been opened the IC chip at least partially fails to normally operate.
As such, when the housing body housing the IC card is opened the IC circuit does not operate normally. Thus, if the IC card is improperly obtained and opened, it is extremely difficult to find the function of the IC card. Thus the IC card can obtain an enhanced data security.
Preferably the IC circuit includes a data storage unit disposed to store data wherein once the exposure detection unit detects the opened condition the data storage unit has the data at least partially rendered non-extractable.
As such, once the IC card has been opened the data storage unit has the data at least partially rendered non-extractable. Thus it is extremely difficult to obtain important data when the IC card is improperly opened.
Still preferably, the data storage unit has the data at least partially prohibited from being read once the exposure detection unit detects the opened condition.
As such, the data in the data storage unit cannot be read ones the housing body housing the IC card has been opened. The IC card may also be conveniently configured to allow the data to be read through a particular process if a party concerned does not want a third party to obtain the data but wants to keep the data.
Still preferably in the IC card the data storage unit has the data at least partially erased once the exposure detection unit detects the opened condition.
As such, once the housing body housing the IC card has been opened the data storage unit has the data at least partially erased. Thus, once the housing body has been opened no one can obtain the data. Thus the IC card can be provided with an extremely enhanced data security.
Still preferably, the IC card is comprised of a data processing unit disposed to process data wherein the data processing unit has a function at least partially stopped once the exposure detection unit detects the opened condition.
As such, the data processing unit has a function at least partially failing to function once the housing body housing the IC card has been opened. Thus, it is extremely difficult to know the function of the data processing unit if the IC card is improperly obtained and opened.
Preferably the exposure detection unit detects the opened condition by detecting external light entering when the housing body is opened.
As such, the opened condition can readily be detected, e.g., via a light receiving element arranged in the housing body.
Still preferably, as the exposure detection unit a plurality of light receiving elements are arranged in parallel.
For example, a plurality of small light-receiving elements may be arranged in the housing body to less noticeably arrange the elements. The plurality of light receiving elements can also be dispersedly arranged to detect the opened condition over a wide range of area.
Still preferably, the exposure detection unit detects the opened condition by detecting a variation in electrostatic capacitance that is introduced when the housing body is opened.
As such, the opened condition can be detected, e.g., if a capacitor defined by at least a portion of the housing body has an electrostatic capacitance varying when the housing body is opened.
Still preferably, the exposure detection unit detects the opened condition by detecting a variation in resistance that is introduced when the housing body is opened.
As such, the opened condition can be detected, e.g., if a resistor defined by at least a portion of the housing body has a value of resistance that varies when the housing body is opened.
Still preferably, the exposure detection unit detects the opened condition by detecting disconnection of a predetermined interconnection that is caused when the housing body is opened.
As such, the opened condition can be detected, e.g., if an interconnection arranged at at least a portion of the housing body is adapted to be disconnected when the housing body is opened.
In another aspect of the present invention, an IC chip module with at least two members integrally formed is comprised of an IC circuit provided at at least one of the members, characterized in that there is provided a exposure detection unit detecting opened condition of the IC chip module, wherein once the exposure detection unit detects the opened condition the IC circuit at least partially fails to normally function.
Preferably, the IC circuit includes a data storage unit disposed to store data, wherein once the exposure detection unit detects the opened condition the data storage unit has the data at least partially rendered non-extractable.
Still preferably, the data storage unit has the data at least partially prohibited from being read once the exposure detection detects the opened condition.
Still preferably, the data stored in the data storage unit is partially erased once the exposure detection unit detects the opened condition.
Still preferably, the IC circuit includes a data processing unit having a function at least partially stopped once the exposure detection unit detects the opened condition.
Still preferably, the exposure detection unit detects the opened condition by detecting external light entering when the IC chip module is opened.
Still preferably, the exposure detection unit is a plurality of light receiving elements arranged in parallel.
Still preferably, the exposure detection unit detects the opened condition by detecting a variation in electrostatic capacitance that is introduced when the IC chip module is opened.
Still preferably, the exposure detection unit detects the opened condition by detecting a variation in a value of resistance that is introduced when the IC chip module is opened.
Still preferably, the exposure detection unit detects the opened condition by detecting disconnection of a predetermined interconnection that is caused when the IC chip module is opened.
Still preferably, the exposure detection unit is at least partially defined by a portion of the IC chip circuit provided in the IC chip.
As such, the exposure detection unit is hardly recognized in the geometry of the IC chip, resulting in an enhanced data security. Furthermore, incorporating a portion or the entirety of the exposure detection unit into the IC chip in fabricating the IC chip can reduce the cost for manufacturing the IC card or the IC chip module.
Still preferably, the exposure detection unit detects the opened condition via a light receiving element detecting external light entering when the housing body is opened, wherein the light receiving element is defined by a portion of the IC circuit provided in the IC chip.
As such, a light receiving element such as a photodiode readily formed using the IC circuit, can be used to readily incorporate the exposure detection unit. It is also convenient if a plurality of small light receiving elements are dispersedly incorporated, since such light receiving elements are further hardly recognized in the geometry of the IC chip.